The present invention relates to a real time beamforming apparatus which utilizes a surface acoustic wave device.
Beamforming can be accomplished with a linear array of listening elements, such as passive hydrophones. The beamforming is accomplished by providing an appropriate delay or phase shift to the outputs from the listening elements so as to obtain a maximum summation thereof. This is called steering the beam, and will provide information on the direction of a target from the linear array of listening elements. A basic patent on the delay line technique for beamforming is illustrated in the patent to G. W. Dewitz, U.S. Pat. No. 3,037,185.
Other techniques for performing the function of beamforming are frequency scanning or digital beamforming. Digital beamformers are presently not practical for listening arrays with high frequencies except for systems where cost and complexity are no object. Frequency scanning has been utilized, however this type of system requires considerably more complicated filtering. Both the digital beamformers and the frequency scanners are costly and bulky.